Integrated molecular subtyping defines a curable oligometastatic state in colorectal liver metastasis

Optimizing Loco Regional Management of Oligometastatic Colorectal Cancer: Technical Aspects and Biomarkers, Two Sides of the Same Coin

Colorectal cancer (CRC) is the third most common cancer worldwide and has a high rate of metastatic disease which is the main cause of CRC-related death. Oligometastatic disease is a clinical condition recently included in ESMO guidelines that can benefit from a more aggressive locoregional approach. This review focuses the attention on colorectal liver metastases (CRLM) and highlights recommendations and therapeutic locoregional strategies drawn from the current literature and consensus conferences. The different percutaneous therapies (radiofrequency ablation, microwave ablation, irreversible electroporation) as well as trans-arterial approaches (chemoembolization and radioembolization) are discussed. Ablation margins, the choice of the imaging guidance as well as characteristics of the different ablation techniques and other technical aspects are analyzed. A specific attention is then paid to the increasing role of biomarkers (in particular molecular profiling) and their role in the selection of the proper treatment for the right patient. In conclusion, in this review an up-to-date state of the art of the application of locoregional treatments on CRLM is provided, highlighting both technical aspects and the role of biomarkers, two sides of the same coin.

Prognostic and Predictive Biomarkers in Oligometastatic Disease

Metastatic lesions are largely responsible for cancer-related deaths and are synonymous with a poor prognosis. However, this is not always true for patients with oligometastases whose disease may be amenable to curative-intent local therapies. It has been proposed that an "intermediate state" (oligometastasis) exists in between locoregional and advanced disease states; however, the clinical definition of oligometastasis varies, and there is limited understanding of how tumor biology differs between oligometastases and polymetastases. There is evidence that local therapies can extend survival in patients with oligometastases, yet patient selection for local intervention and/or systemic therapy remains a challenge. Prognostic and predictive biomarkers of oligometastatic disease are strongly needed to identify patient candidates most likely to gain survival benefit from local therapies and to aid in the incorporation of ablative treatments in the context of existing systemic therapies.

Circulating Tumor DNA Biomarkers for Early Detection of Oligometastasis

Oligometastasis represents an intermediate disease stage between localized and widely metastatic cancer. Efficient identification of patients with oligometastasis remains a barrier for accrual on clinical trials of oligometastasis-directed therapy. Here we review the prospect of circulating tumor DNA-based monitoring to promote sensitive, specific, and cost-efficient detection of cancer recurrence during posttreatment surveillance. Thus, an impetus for the development and implementation of clinical-grade circulating tumor DNA assays should be for the positive impact they will have on clinical investigations of oligometastasis-directed therapy.

Radiotherapy in the Management of Metastatic Hormone-Sensitive Prostate Cancer: What Is the Standard of Care?

Systemic therapy has historically been the backbone of treatment for patients with metastatic disease. However, recent evidence suggests metastasis-directed therapy in those with oligometastatic disease (≤5 lesions) may improve progression-free and overall survival. Within prostate cancer-specific cohorts, metastasis-directed therapy also appears to delay the time to initiation of androgen deprivation therapy while also generally being associated with a mild toxicity profile and has thus garnered interest as a means to delay systemic therapy. Here we review the evidence surrounding the use of radiation therapy to metastatic sites in patients with metastatic hormone-sensitive prostate cancer.

Definition, Biology, and History of Oligometastatic and Oligoprogressive Disease

Historical theories of metastasis have been informed by the seed and soil hypothesis, the Halsteadian paradigm proposing an orderly spread from local to distant sites, and the presumption that cancer is an inherently systemic process even in the earliest cases. The more contemporary spectrum theory now suggests that the propensity for distant spread exists along a continuum of metastatic virulence. Tumors with limited metastatic potential represent one subset along this spectrum that could potentially be cured with local ablative therapy. Integrating clinical and molecular features to biologically inform the classification of not only oligometastatic or oligoprogressive disease but also the entire metastatic spectrum holds great promise to improve prognostication and inform clinical decision making. To this end, the inclusion of molecular correlative studies and biospecimen collection on prospective protocols is imperative.

Oligometastatic and Oligoprogression Disease and Local Therapies in Prostate Cancer

Our understanding of metastatic disease is rapidly advancing, with recent evidence supporting an oligometastatic state currently defined by patients having a limited (typically ≤5) number of metastatic deposits. The optimal management of these patients is also shifting toward increased integration of local therapies, with emerging evidence suggesting metastasis-directed therapy can improve overall survival. Additionally, the use of stereotactic ablative radiation therapy within castration-sensitive oligometastatic prostate cancer cohorts appears to forestall the need to initiate systemic therapy, which has unfavorable side effect profiles, such as androgen deprivation therapy, while itself being associated with little toxicity. We review the literature surrounding the use of metastasis-directed therapy in the treatment of oligometastatic prostate cancer by reviewing the evidence for its use within 3 subgroups: de novo synchronous, oligorecurrent, and oligoprogressive disease.

Copy number and transcriptome alterations associated with metastatic lesion response to treatment in colorectal cancer

BACKGROUND

Therapeutic resistance is the main cause of death in metastatic colorectal cancer. To investigate genomic plasticity, most specifically of metastatic lesions, associated with response to first-line systemic therapy, we collected longitudinal liver metastatic samples and characterized the copy number aberration (CNA) landscape and its effect on the transcriptome.

METHODS

Liver metastatic biopsies were collected prior to treatment (pre, n = 97) and when clinical imaging demonstrated therapeutic resistance (post, n = 43). CNAs were inferred from whole exome sequencing and were correlated with both the status of the lesion and overall patient progression-free survival (PFS). We used RNA sequencing data from the same sample set to validate aberrations as well as independent datasets to prioritize candidate genes.

RESULTS

We identified a significantly increased frequency gain of a unique CN, in liver metastatic lesions after first-line treatment, on chr18p11.32 harboring 10 genes, including TYMS, which has not been reported in primary tumors (GISTIC method and test of equal proportions, FDR-adjusted p = 0.0023). CNA lesion profiles exhibiting different treatment responses were compared and we detected focal genomic divergences in post-treatment resistant lesions but not in responder lesions (two-tailed Fisher's Exact test, unadjusted p ≤ 0.005). The importance of examining metastatic lesions is highlighted by the fact that 15 out of 18 independently validated CNA regions found to be associated with PFS in this study were only identified in the metastatic lesions and not in the primary tumors.

CONCLUSION

This investigation of genomic-phenotype associations in a large colorectal cancer liver metastases cohort identified novel molecular features associated with treatment response, supporting the clinical importance of collecting metastatic samples in a defined clinical setting.

Emerging Paradigm of Consolidative Thoracic Radiotherapy in Oligometastatic NSCLC

The concept of oligometastatic disease has evolved substantially over the past decade. During this time, there has been a transition from retrospective and single-arm prospective studies to randomized evidence suggesting a benefit of local consolidative therapy (LCT) in the setting of limited metastatic non-small cell lung cancer. These trials had constraints and were thus limited in the strength of their conclusions, but led to several other ongoing randomized trials examining the role of LCT. These studies span various disease states (synchronous oligometastatic vs oligoprogressive), the scope of histologies included, and in how they define oligometastases. In addition, parallel biologic work is attempting to integrate relevant biomarkers and molecular classifications, with the ultimate goal of more precisely defining oligometastases and triaging patients to appropriate care. Finally, consensus guidelines have been initiated that provide a framework for designing future studies and for maintaining consistency across analyses that will facilitate the interpretation of results. This review describes the prior randomized data, the limitations therein, and future directions of clinical and preclinical studies that highlight the emerging paradigms for treatment of this select patient cohort.

Optimizing the Treatment Schedule of Radiotherapy Combined With Anti-PD-1/PD-L1 Immunotherapy in Metastatic Cancers

Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein-1 (PD-1), and programmed cell death ligand-1 (PD-L1) have been approved for a variety of malignant tumors and are widely used to treat patients with metastatic disease. However, the efficacy of PD-1 inhibitors is limited due to tumor heterogeneity, high tumor burden, and "cold" tumor microenvironment. Radiotherapy can improve the anti-tumor effects of PD-1/PD-L1 inhibitors in various ways. As a new radiotherapy method, stereotactic body radiotherapy (SBRT) or hypofractionated radiotherapy (HFRT) provides higher doses per fraction to the target lesions, thus achieving immune activation effects and overcoming tumor resistance to anti-PD-1/PD-L1 treatment, which significantly improves the local and distant control of tumors. However, for different metastatic situations, radiotherapy plays different roles in the combination therapy. In oligometastatic status, radiotherapy can be used as a local radical treatment aiming to eliminate cancers in cooperation with systemic PD-1 inhibitors. In other circumstances, like bulky metastasis or multiple metastatic tumors, radiotherapy can be used as adjuvant to systemic immunotherapy. This review focuses on the underlying mechanisms and optimization strategies for the combination of radiotherapy and anti-PD-1/PD-L1 therapy in metastatic disease.

Cost-Effectiveness Analysis of Local Ablation and Surgery for Liver Metastases of Oligometastatic Colorectal Cancer

BACKGROUND

Colorectal cancer is among the most prevalent cancer entities worldwide, with every second patient developing liver metastases during their illness. For local treatment of liver metastases, a surgical approach as well as ablative treatment options, such as microwave ablation (MWA) and radiofrequency ablation (RFA), are available. The aim of this study is to evaluate the cost-effectiveness of RFA, MWA and surgery in the treatment of liver metastases of oligometastatic colorectal cancer (omCRC) that are amenable for all investigated treatment modalities.

METHODS

A decision analysis based on a Markov model assessed lifetime costs and quality-adjusted life years (QALY) related to the treatment strategies RFA, MWA and surgical resection. Input parameters were based on the best available and most recent evidence. Probabilistic sensitivity analyses (PSA) were performed with Monte Carlo simulations to evaluate model robustness. The percentage of cost-effective iterations was determined for different willingness-to-pay (WTP) thresholds.

RESULTS

The base-case analysis showed that surgery led to higher long-term costs compared to RFA and MWA (USD 41,848 vs. USD 36,937 vs. USD 35,234), while providing better long-term outcomes than RFA, yet slightly lower than MWA (6.80 vs. 6.30 vs. 6.95 QALYs for surgery, RFA and MWA, respectively). In PSA, MWA was the most cost-effective strategy for all WTP thresholds below USD 80,000 per QALY.

CONCLUSIONS

In omCRC patients with liver metastases, MWA and surgery are estimated to provide comparable efficacy. MWA was identified as the most cost-effective strategy in intermediate resource settings and should be considered as an alternative to surgery in high resource settings.

The CK1δ/ε-AES axis regulates tumorigenesis and metastasis in colorectal cancer

Background: Amino-terminal enhancer of split (AES) has been identified as a tumor and metastasis suppressor in some cancers including colorectal cancer (CRC), but very little is known about the regulation of AES expression.

Methods: Bioinformatics analysis was used to investigate the expression patterns of AES, CK1δ and CK1ε. The co-immunoprecipitation, GST pull-down, Western Blot, real-time PCR and immunohistochemistry were performed to study the mechanism underlying the regulation of AES expression by CK1δ/ε. The biological function was assessed by in vitro colony formation, transwell, sphere formation, tumor organoids, in vivo tumor metastasis model and patient-derived colorectal tumor xenografts (PDTX) model.

Results: A strong inverse relationship was observed between the expression of AES and the expression of CK1δ/ε. Mechanically, AES could interact with CK1δ/ε and SKP2 using its Q domain. SKP2 mediated the ubiquitination and degradation of AES in a CK1δ/ε-dependent manner. CK1δ/ε phosphorylated AES at Ser121 and accelerated the SKP2-mediated ubiquitination and degradation of AES. In colon cancer cells, CK1δ/ε antagonized the effect of wild-type AES but not that of its mutant (S121A) on Wnt and Notch signaling, leading to an increase in the expression of Wnt target genes and Notch target genes. By downregulating the expression of AES, CK1δ/ε enhanced anchorage-independent growth, migration, invasion and sphere formation in colon cancer cells. CK1δ/ε also promoted the growth of APC^min/+ colorectal tumor organoids and liver metastasis in colon cancer mouse models through the regulation of AES degradation. Furthermore, CK1 inhibitor SR3029 treatment suppressed tumor growth via stabilizing AES in APC^min/+ colorectal tumor organoids and patient-derived colorectal tumor xenografts (PDTX).

Conclusions: Our results revealed that the CK1δ/ε-AES axis is important for CRC tumorigenesis and metastasis, and targeted inhibition of this axis may be a potential therapeutic strategy for CRC.

X-change symposium: status and future of modern radiation oncology-from technology to biology

Future radiation oncology encompasses a broad spectrum of topics ranging from modern clinical trial design to treatment and imaging technology and biology. In more detail, the application of hybrid MRI devices in modern image-guided radiotherapy; the emerging field of radiomics; the role of molecular imaging using positron emission tomography and its integration into clinical routine; radiation biology with its future perspectives, the role of molecular signatures in prognostic modelling; as well as special treatment modalities such as brachytherapy or proton beam therapy are areas of rapid development. More clinically, radiation oncology will certainly find an important role in the management of oligometastasis. The treatment spectrum will also be widened by the rational integration of modern systemic targeted or immune therapies into multimodal treatment strategies. All these developments will require a concise rethinking of clinical trial design. This article reviews the current status and the potential developments in the field of radiation oncology as discussed by a panel of European and international experts sharing their vision during the "X-Change" symposium, held in July 2019 in Munich (Germany).

(Oligo)metastasis as a Spectrum of Disease

Cancer metastasis is the leading cause of cancer-related mortality, and most patients with metastases from solid tumors have historically been considered incurable. Here, we discuss the evolution of our understanding of the oligometastatic state with an emphasis on the view that cancer metastasis represents a spectrum of disease. We highlight several recently published prospective clinical trials demonstrating improvements in cancer-specific outcomes with the utilization of metastasis-directed local therapies. We discuss biological aspects of oligometastases, including genetic, epigenetic, and immune determinants of the metastatic spectrum. Finally, we propose future considerations regarding clinical trial design for patients with oligometastatic disease.

Radiosensitizing Chemotherapy (Irinotecan) with Stereotactic Body Radiation Therapy for the Treatment of Inoperable Liver and/or Lung Metastases of Colorectal Cancer

Simple Summary

Stereotactic body radiotherapy (SBRT) is a recognized treatment for liver or lung metastases, but radiosensitivity of colorectal cancer could be lower than other primary cancers. We postulated that local responses could be improved by SBRT with a concomitant radiosensitizing agent (irinotecan). RADIOSTEREO-CAMPTO was a prospective multi-center phase 2 trial conducted between 2008 and 2013. We confirmed that SBRT-Irinotecan was a short, effective and well-tolerated treatment, with no worsening of the quality of life. It allowed for several months of chemotherapy-free periods despite most patients receiving multiple prior lines of treatment. Radiosensitizing irinotecan was able to compensate for lower SBRT dose than nowadays used for liver and lung metastases and could be an interesting regimen in case of tumour-surrounding healthy tissues requiring limited radiation dose.

Abstract

Background: Stereotactic body radiotherapy (SBRT) is a recognized treatment for colorectal cancer (CRC) metastases. We postulated that local responses could be improved by SBRT with a concomitant radiosensitizing agent (irinotecan). Methods: RADIOSTEREO-CAMPTO was a prospective multi-center phase 2 trial investigating SBRT (40–48 Gy in 4 fractions) for liver and/or lung inoperable CRC oligometastases (≤3), combined with two weekly intravenous infusions of 40 mg/m² Irinotecan. Primary outcome was the objective local response rate as per RECIST. Secondary outcomes were early and late toxicities, EORTC QLQ-C30 quality of life, local control and overall survival. Results: Forty-four patients with 51 lesions (liver = 39, lungs = 12) were included. Median age was 69 years (46–84); 37 patients (84%) had received at least two prior chemotherapy treatments. Median follow-up was 48.9 months. One patient with two lung lesions was lost during follow-up. Assuming maximum bias hypothesis, the objective local response rate in ITT was 86.3% (44/51—95% CI: [76.8–95.7]) or 82.4% (42/51—95% CI: [71.9–92.8]). The observed local response rate was 85.7% (42/49—95% CI: [75.9–95.5]). The 1 and 2-year local (distant) progression-free survivals were 84.2% (38.4%) and 67.4% (21.3%), respectively. The 1 and 2-year overall survivals were 97.5% and 75.5%. There were no severe acute or late reactions. The EORTC questionnaire scores did not significantly worsen during or after treatment. Conclusions: SBRT with irinotecan was well tolerated with promising results despite heavily pretreated patients.

Metastasis directed stereotactic radiotherapy in NSCLC patients progressing under targeted- or immunotherapy: efficacy and safety reporting from the 'TOaSTT' database

Background

Metastasis directed treatment (MDT) is increasingly performed with the attempt to improve outcome in non-small cell lung cancer (NSCLC) patients receiving targeted- or immunotherapy (TT/IT). This study aimed to assess the safety and efficacy of metastasis directed stereotactic radiotherapy (SRT) concurrent to TT/IT in NSCLC patients.

Methods

A retrospective multicenter cohort of stage IV NSCLC patients treated with TT/IT and concurrent (≤ 30 days) MDT was established. 56% and 44% of patients were treated for oligoprogressive disease (OPD) or polyprogressive disease (PPD) under TT/IT, polyprogressive respectively. Survival was analyzed using Kaplan–Meier and log rank testing. Toxicity was scored using CTCAE v4.03 criteria. Predictive factors for overall survival (OS), progression free survival (PFS) and time to therapy switch (TTS) were analyzed with uni- and multivariate analysis.

Results

MDT of 192 lesions in 108 patients was performed between 07/2009 and 05/2018. Concurrent TT/IT consisted of EGFR/ALK-inhibitors (60%), immune checkpoint inhibitors (31%), VEGF-antibodies (8%) and PARP-inhibitors (1%). 2y-OS was 51% for OPD and 25% for PPD. After 1 year, 58% of OPD and 39% of PPD patients remained on the same TT/IT. Second progression after MDT was oligometastatic (≤ 5 lesions) in 59% of patients. Severe acute and late toxicity was observed in 5.5% and 1.9% of patients. In multivariate analysis, OS was influenced by the clinical metastatic status (p = 0.002, HR 2.03, 95% CI 1.30–3.17). PFS was better in patients receiving their first line of systemic treatment (p = 0.033, HR 1.7, 95% CI 1.05–2.77) and with only one metastases-affected organ (p = 0.023, HR 2.04, 95% CI 1.10–3.79). TTS was 6 months longer in patients with one metastases-affected organ (p = 0.031, HR 2.53, 95% CI 1.09–5.89). Death was never therapy-related.

Conclusions

Metastases-directed SRT in NSCLC patients can be safely performed concurrent to TT/IT with a low risk of severe toxicity. To find the ideal sequence of the available multidisciplinary treatment options for NSCLC and determine what patients will benefit most, a further evaluated in a broader context within prospective clinical trials is needed continuation of TT/IT beyond progression combined with MDT for progressive lesions appears promising but requires prospective evaluation.

Trial registration: retrospectively registered

The Mutational Landscape of Metastatic Castration-sensitive Prostate Cancer: The Spectrum Theory Revisited

BACKGROUND

Emerging data suggest that metastasis is a spectrum of disease burden rather than a binary state, and local therapies, such as radiation, might improve outcomes in oligometastasis. However, current definitions of oligometastasis are solely numerical.

OBJECTIVE

To characterize the somatic mutational landscape across the disease spectrum of metastatic castration-sensitive prostate cancer (mCSPC) to elucidate a biological definition of oligometastatic CSPC.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective study of men with mCSPC who underwent clinical-grade sequencing of their tumors (269 primary tumor, 25 metastatic sites). Patients were classified as having biochemically recurrent (ie, micrometastatic), metachronous oligometastatic (≤5 lesions), metachronous polymetastatic (>5 lesions), or de novo metastatic (metastasis at diagnosis) disease.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We measured the frequency of driver mutations across metastatic classifications and the genomic associations with radiographic progression-free survival (rPFS) and time to castrate-resistant prostate cancer (CRPC).

RESULTS AND LIMITATIONS

The frequency of driver mutations in TP53 (p =  0.01), WNT (p =  0.08), and cell cycle (p =  0.04) genes increased across the mCSPC spectrum. TP53 mutation was associated with shorter rPFS (26.7 vs 48.6 mo; p =  0.002), and time to CRPC (95.6 vs 155.8 mo; p =  0.02) in men with oligometastasis, and identified men with polymetastasis with better rPFS (TP53 wild-type, 42.7 mo; TP53 mutated, 18.5 mo; p =  0.01). Mutations in TP53 (incidence rate ratio [IRR] 1.45; p =  0.004) and DNA double-strand break repair (IRR 1.61; p <  0.001) were associated with a higher number of metastases. Mutations in TP53 were also independently associated with shorter rPFS (hazard ratio [HR] 1.59; p =  0.03) and the development of CRPC (HR 1.71; p =  0.01) on multivariable analysis. This study was limited by its retrospective nature, sample size, and the use of commercially available sequencing platforms, resulting in a limited predefined set of genes examined.

CONCLUSIONS

Somatic mutational profiles reveal a spectrum of metastatic biology that helps in redefining oligometastasis beyond a simple binary state of lesion enumeration.

PATIENT SUMMARY

Oligometastatic prostate cancer is typically defined as less than three to five metastatic lesions and evidence suggests that using radiation or surgery to treat these sites improves clinical outcomes. As of now, treatment decisions for oligometastasis are solely defined according to the number of lesions. However, this study suggests that tumor mutational profiles can provide a biological definition of oligometastasis and complement currently used numerical definitions.

Outcomes of Observation vs Stereotactic Ablative Radiation for Oligometastatic Prostate Cancer: The ORIOLE Phase 2 Randomized Clinical Trial

Question

How effectively does stereotactic ablative radiotherapy prevent progression of disease compared with observation in men with recurrent hormone-sensitive prostate cancer with 1 to 3 metastases?

Findings

In this phase 2 randomized clinical trial of 54 men, progression of disease at 6 months occurred in 7 of 36 participants (19%) treated with stereotactic ablative radiotherapy and in 11 of 18 participants (61%) undergoing observation, a statistically significant difference.

Meaning

Stereotactic ablative radiotherapy is a promising treatment approach for men with recurrent hormone-sensitive oligometastatic prostate cancer who wish to delay initiation of androgen deprivation therapy.

Importance

Complete metastatic ablation of oligometastatic prostate cancer may provide an alternative to early initiation of androgen deprivation therapy (ADT).

Objective

To determine if stereotactic ablative radiotherapy (SABR) improves oncologic outcomes in men with oligometastatic prostate cancer.

Design, Setting, and Participants

The Observation vs Stereotactic Ablative Radiation for Oligometastatic Prostate Cancer (ORIOLE) phase 2 randomized study accrued participants from 3 US radiation treatment facilities affiliated with a university hospital from May 2016 to March 2018 with a data cutoff date of May 20, 2019, for analysis. Of 80 men screened, 54 men with recurrent hormone-sensitive prostate cancer and 1 to 3 metastases detectable by conventional imaging who had not received ADT within 6 months of enrollment or 3 or more years total were randomized.

Interventions

Patients were randomized in a 2:1 ratio to receive SABR or observation.

Main Outcomes and Measures

The primary outcome was progression at 6 months by prostate-specific antigen level increase, progression detected by conventional imaging, symptomatic progression, ADT initiation for any reason, or death. Predefined secondary outcomes were toxic effects of SABR, local control at 6 months with SABR, progression-free survival, Brief Pain Inventory (Short Form)–measured quality of life, and concordance between conventional imaging and prostate-specific membrane antigen (PSMA)–targeted positron emission tomography in the identification of metastatic disease.

Results

In the 54 men randomized, the median (range) age was 68 (61-70) years for patients allocated to SABR and 68 (64-76) years for those allocated to observation. Progression at 6 months occurred in 7 of 36 patients (19%) receiving SABR and 11 of 18 patients (61%) undergoing observation (P = .005). Treatment with SABR improved median progression-free survival (not reached vs 5.8 months; hazard ratio, 0.30; 95% CI, 0.11-0.81; P = .002). Total consolidation of PSMA radiotracer-avid disease decreased the risk of new lesions at 6 months (16% vs 63%; P = .006). No toxic effects of grade 3 or greater were observed. T-cell receptor sequencing identified significant increased clonotypic expansion following SABR and correlation between baseline clonality and progression with SABR only (0.082085 vs 0.026051; P = .03).

Conclusions and Relevance

Treatment with SABR for oligometastatic prostate cancer improved outcomes and was enhanced by total consolidation of disease identified by PSMA-targeted positron emission tomography. SABR induced a systemic immune response, and baseline immune phenotype and tumor mutation status may predict the benefit from SABR. These results underline the importance of prospective randomized investigation of the oligometastatic state with integrated imaging and biological correlates.

Trial Registration

ClinicalTrials.gov Identifier: NCT02680587

Safety and Survival Rates Associated With Ablative Stereotactic Radiotherapy for Patients With Oligometastatic Cancer: A Systematic Review and Meta-analysis

Importance

The oligometastatic paradigm postulates that patients with a limited number of metastases can be treated with ablative local therapy to each site of disease with curative intent. Stereotactic ablative radiotherapy (SABR) is a radiation technique that has become widely used in this setting. However, prospective data are limited and are mainly from single institutional studies.

Objective

To conduct a meta-analysis to characterize the safety and clinical benefit of SABR in oligometastatic cancer.

Data Sources

A comprehensive search was conducted in PubMed/MEDLINE, Embase, Cochrane Database of Systematic Reviews, and Cumulative Index to Nursing and Allied Health Literature on December 23, 2019, that included prospective clinical trials and review articles that were published within the past 15 years.

Study Selection

Inclusion criteria were single-arm or multiarm prospective trials including patients with oligometastatic cancer (ie, ≤5 sites of extracranial disease), and SABR was administered in less than or equal to 8 fractions with greater than or equal to 5 Gy/fraction.

Data Extraction and Synthesis

The Population, Intervention, Control, Outcomes and Study Design; Preferred Reporting Items for Systematic Reviews and Meta-analyses; and Meta-analysis of Observational Studies in Epidemiology methods were used to identify eligible studies. Study eligibility and data extraction were reviewed by 3 authors independently. Random-effects meta-analyses using the Knapp-Hartung correction, arcsine transformation, and restricted maximum likelihood method were conducted.

Main Outcomes and Measures

Safety (acute and late grade 3-5 toxic effects) and clinical benefit (1-year local control, 1-year overall survival, and 1-year progression-free survival).

Results

Twenty-one studies comprising 943 patients and 1290 oligometastases were included. Median age was 63.8 years (interquartile range, 59.6-66.1 years) and median follow-up was 16.9 months (interquartile range, 13.7-24.5 months). The most common primary sites were prostate (22.9%), colorectal (16.6%), breast (13.1%), and lung (12.8%). The estimate for acute grade 3 to 5 toxic effect rates under the random-effects models was 1.2% (95% CI, 0%-3.8%; I2 = 50%; 95% CI, 3%-74%; and τ = 0.20%; 95% CI, 0.00%-1.43%), and the estimate for late grade 3 to 5 toxic effects was 1.7% (95% CI, 0.2%-4.6%; I2 = 54%; 95% CI, 11%-76%; and τ = 0.25%; 0.01%-1.00%). The random-effects estimate for 1-year local control was 94.7% (95% CI, 88.6%-98.6%; I2 = 90%; 95% CI, 86%-94%; and τ = 0.81%; 95% CI, 0.36%-2.38%]). The estimate for 1-year overall survival was 85.4% (95% CI, 77.1%-92.0%; I2 = 82%; 95% CI, 71%-88%; and τ = 0.72%; 95% CI, 0.30%-2.09%) and 51.4% (95% CI, 42.7%-60.1%; I2 = 58%; 95% CI, 17%-78%; and τ = 0.20%; 95% CI, 0.02%-1.21%) for 1-year progression-free survival.

Conclusions and Relevance

In this meta-analysis, SABR appears to be relatively safe in patients with oligometastatic cancer with clinically acceptable rates of acute and late grade 3 to 5 toxic effects less than 13% and with clinically acceptable rates of 1-year local control overall survival, and progression-free survival. These findings are hypothesis generating and require validation by ongoing and planned prospective clinical trials.

Modern therapeutic approaches for the treatment of malignant liver tumours

Malignant liver tumours include a wide range of primary and secondary tumours. Although surgery remains the mainstay of curative treatment, modern therapies integrate a variety of neoadjuvant and adjuvant strategies and have achieved dramatic improvements in survival. Extensive tumour loads, which have traditionally been considered unresectable, are now amenable to curative treatment through systemic conversion chemotherapies followed by a variety of interventions such as augmentation of the healthy liver through portal vein occlusion, staged surgeries or ablation modalities. Liver transplantation is established in selected patients with hepatocellular carcinoma but is now emerging as a promising option in many other types of tumour such as perihilar cholangiocarcinomas, neuroendocrine or colorectal liver metastases. In this Review, we summarize the available therapies for the treatment of malignant liver tumours, with an emphasis on surgical and ablative approaches and how they align with other therapies such as modern anticancer drugs or radiotherapy. In addition, we describe three complex case studies of patients with malignant liver tumours. Finally, we discuss the outlook for future treatment, including personalized approaches based on molecular tumour subtyping, response to targeted drugs, novel biomarkers and precision surgery adapted to the specific tumour.

Metastasis-directed therapy for oligometastasis and beyond

Metastasis-directed therapy (MDT)-local therapy that is intended to eradicate specific metastatic lesions-has hitherto been used with varying degrees of clinical efficacy and acceptance as a meaningful therapy for metastatic disease. Over the past 25 years, however, the momentum for using MDT to manage patients with metastatic solid tumours has increased, driven by several factors. Among these factors is the recognition that patients with limited metastatic burden could potentially derive survival benefits from MDT. Furthermore, although current systemic therapies are increasingly effective, they are infrequently curative. In addition, technological advances have broadened the spectrum of metastatic lesions that can be treated with ablative intent. Here we aim to briefly review the status of evidence for the clinical benefit of MDT based on current data mainly from trials in patients with oligometastatic disease, discuss the myriad of clinical states that might fall under and beyond the definition of oligometastasis, review technological advances in MDT and their applications beyond oligometastasis, and discuss the need for the continued co-evolution of MDT and systemic therapy as we seek to understand which patients with metastatic cancer can achieve durable remission and how to optimally manage those who cannot.

Therapeutic Concepts for Oligometastatic Gastrointestinal Tumours

Background

Clinical trials have proven a survival benefit from applying local therapies for oligometastatic cancers of various origin.

Summary

Today, the definition of oligometa-static disease is based on limited lesion numbers and organ systems involved. Treatment guidelines by the European Organisation for Research and Treatment of Cancer (EORTC), European Society for Medical Oncology (ESMO) and several other groups suggest a threshold of up to 5 tumours. Established biological markers indicating the aggressiveness of a given tumour (and therefore suggesting local treatment only or the addition of or complete switch to systemic therapies) are missing, except for disease-free survival, the only recommended parameter for patient selection beyond lesion count.

Key Message

The following article discusses clinical implications as well as local techniques established for the treatment of oligometastatic disease.

Targeting Oligometastasis with Stereotactic Ablative Radiation Therapy or Surgery in Metastatic Hormone-sensitive Prostate Cancer: A Systematic Review of Prospective Clinical Trials

CONTEXT

Metastasis-directed therapy (MDT) in the form of stereotactic ablative radiation therapy (SABR), or in combination with surgical metastasectomy, may have a role in cancer control and disease progression.

OBJECTIVE

To perform a systematic review of MDT (surgery or SABR) for oligometastatic (up to 10 metastases, recurrent or de novo) hormone-sensitive prostate cancer in addition to or following primary prostate gland treatment.

EVIDENCE ACQUISITION

Medline, Embase, Cochrane Review Database, and clinical trial Databases were systematically searched for clinical trials reporting oncological outcomes and safety. The risk of bias was assessed with the Cochrane 2.0 or ROBINS-I tool.

EVIDENCE SYNTHESIS

From 1025 articles identified, four clinical trials met the prespecified criteria. These included two randomised and two nonrandomised clinical trials (n=169). Baseline prostate-specific antigen level, age, and metastasis ranged from 2.0 to 17.0 ng/ml, 43 to 75 yr, and one to seven lesions, respectively. Nodal, bone, nodal and bone, and visceral metastases were present in 49.7% (84/169), 33.7% (57/169), 15.9% (27/169), and 0.5% (1/169) of patients, respectively. Diagnostic conventional imaging was used in 43.7% (74/169) and positron emission tomography/computerised tomography in 56.2% (95/169) of patients. SABR and surgical metastasectomy with SABR were used in 78.3% (94/120) and 21.6% (26/120) of patients, respectively. Early progression-free survival ranged from 19% to 60%. Local control was reported as 93-100%. Grade II and III SABR toxicities were reported in 8% (8/100) and 1% (1/100) of patients, respectively. Grade IIIa and IIIb surgical complications were reported in 7.69% (2/26) and 0% (0/26) of patients, respectively.

CONCLUSIONS

MDT is a promising experimental therapeutic approach in men with hormone-sensitive oligometastatic prostate cancer. Randomised comparative studies are required to ascertain its role and optimal timing in oligometastatic recurrence and efficacy in de novo synchronous disease.

PATIENT SUMMARY

We looked at the evidence regarding the use of surgery or radiotherapy at target areas of cancer spread in men with newly diagnosed or relapsed advanced (metastatic) prostate cancer. Evidence supports both treatment options as promising approaches, but further large trials are required.

Superior outcomes of nodal metastases compared to visceral sites in oligometastatic colorectal cancer treated with stereotactic ablative radiotherapy

BACKGROUND

Stereotactic ablative radiotherapy (SBRT) is a radical option for oligometastatic colorectal cancer (CRC) patients, but most data relate to visceral metastases.

METHODS

A prospective, multi-centre database of CRC patients treated with SBRT was interrogated. Inclusion criteria were ECOG PS 0-2, ≤3 sites of disease, a disease free interval of >6 months unless synchronous liver metastases. Primary endpoints were local control (LC), progression free survival (PFS) and overall survival (OS).

RESULTS

163 patients (172 metastases) were analysed. The median FU was 16 months (IQR 12.2-22.85). The LC at 1 year was 83.8% (CI 76.4%-91.9%) with a PFS of 55% (CI 47%-64.7%) respectively. LC at 1 year was 90% (CI 83%-99%) for nodal metastases (NM), 75% (63%-90%) for visceral metastases (VM). NM had improved median PFS (9 vs 19 months) [HR 0.6, CI 0.38-0.94, p = 0.032] and median OS (32 months vs not reached) [HR 0.28, CI 0.18-0.7, p = 0.0062] than VM, regardless of whether the NM were located inside or outside the pelvis. On multivariate analysis, NM and ECOG PS 0 were significant good prognostic factors. An exploratory analysis suggests KRAS WT is also a good prognostic factor.

CONCLUSION

Nodal site is an important prognostic determinant of SBRT that should incorporated into patient selection. We hypothesise this may have an immunoediting basis.

Liver prometastatic reaction: Stimulating factors and responsive cancer phenotypes

Cancer is first a localized tissue disorder, whose soluble and exosomal molecules and invasive cells induce a host response providing the stromal components of the primary tumor microenvironment (TME). Once the TME is developed, cancer-derived molecules and cells can more efficiently spread out and a whole-body response takes place, whose pathophysiological changes may result in a paraneoplastic syndrome. Remote organ-specific prometastatic reactions may also occur at this time, facilitating metastatic activities of circulating tumor cells (CTCs) through premetastatic niche development at targeted organs. However, additional signaling factors from the inter-organ communication network involved in the pathophysiology and comorbidities of cancer patients may also regulate prometastatic reaction-stimulating effects of cancer and non-cancer tissue factors. This article provides a conceptual overview of our ongoing clinical research on the liver prometastatic reaction (LPR) of patients with colorectal cancer (CRC), their portal vein- and hepatic artery-driven LPR-Stimulating Factors (LPR-SF), and their resulting LPR-derived Metastasis-Stimulating Factors (LPR-MSF) acting on liver-invading CRC cells. In addition, we also provide new insights on the molecular subtyping of LPR-responsive cancer phenotypes in patients with CRC and melanoma; and on how to investigate and interpret the prometastatic infrastructure in the real pathophysiological context of patients with cancer undergoing surgical procedures and receiving pharmacological treatments with multiple side effects, including those affecting the LPR, its stimulating factors and responsive cancer phenotypes.

The Role of Local Treatment in Oligometastatic and Oligoprogressive Cancer

BACKGROUND

Systemic treatment is standard for most types of cancer with disseminated metastases. The role of local treatment (LT) of individual tumor foci in patients with oligometastatic disease is unclear and the object of current scientific studies.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed.

RESULTS

Four randomized trials have shown that radical local treatment confers an advantage with respect to overall survival (OS), compared to systemic treatment alone, in patients with oligometastatic disease. In patients with synchronous metastases and a stable primary tumor, LT prolongs the median overall survival by approximately two years. A single randomized trial for oligometastatic small-cell lung cancer did not show any prolongation of overall survival. Local treatment increased the frequency of grade III side effects by approximately 10%.

CONCLUSION

Although local treatment already has a place in many guidelines on the basis of the findings of a small number of prospective and retrospective studies, a option of local treatment should be considered by an interdisciplinary tumor board individually for suitable patients.

Stereotactic ablative radiotherapy for colorectal cancer liver metastasis

Survival improvement of colorectal liver metastasis (CRLM) benefits from systemic therapy and metastasis-directed local therapy. Stereotactic ablative body radiotherapy (SABR), as a new efficient metastasis-directed local therapy with a systematic impact, plays a vital role in CRLM multidisciplinary treatment. SABR leads to a dramatic immunological change in the tumor microenvironment (TME) via differential activation of cytoprotective and cytotoxic pathways in malignant and non-malignant cells, in addition to direct tumor cell death. The synergy of SABR and immunotherapy might increase the abscopal response rate of out-field lesions by targeting different steps of the immune-mediated response, in addition to direct intratumoral cell death. The clinical treatment and efficacy of SABR, its influence on TME, and potential molecular underpinnings of which are the topic of this review.

The lack of selection criteria for surgery in patients with non-colorectal non-neuroendocrine liver metastases

BACKGROUND

The benefit of surgery in patients with non-colorectal non-neuroendocrine liver metastases (NCRNNELM) remains controversial. At the population level, several statistical prognostic factors and scores have been proposed but inconsistently verified. At the patient level, no selection criteria have been demonstrated to guide individual therapeutic decision making. We aimed to evaluate potential individual selection criteria to predict the benefit of surgery in patients undergoing treatment for NCRNNELM.

METHODS

Data for 114 patients undergoing surgery for NCRNNELM were reviewed. In this population, we identified an early relapse group (ER), defined as patients with unresectable recurrence < 1 year postoperatively who did not benefit from surgery (N = 28), and a long-term survival group (LTS), defined as patients who were recurrence-free ≥ 5 years postoperatively and benefited from surgery (N = 20). Clinicopathologic parameters, the Association Française de Chirurgie (AFC) score, and a modified 4-point Clinical Risk Score (mCRS) (excluding CEA level) were analyzed and compared between LTS and ER groups.

RESULTS

The majority of patients were female and a majority had an ASA score ≤ 2 at the time of liver surgery. The median age was 55 years. Almost half of the patients (46%) presented with a single-liver metastasis. Intermediate- and low-risk AFC scores represented 40% and 60% of the population, respectively. Five- and 10-year overall survival (OS) and disease-free survival (DFS) rates were 56% and 27%, and 30% and 12%, respectively. Negative prognostic factors were the size of liver metastases > 50 mm and delay between primary and NCRNNELM <24 months for OS and DFS, respectively. AFC score was not prognostic while high-risk mCRS (scores 3-4) was predictive for the poorer OS. The clinicopathologic parameters were similar in the ER and LTS groups, except the presence of N+ primary tumor, and the size of liver metastases was significantly higher in the ER group.

CONCLUSION

In patients with resectable NCRNNELM, no predictive factors or scores were found to accurately preoperatively differentiate individual cases in whom surgery would be futile from those in whom surgery could be associated with a significant oncological benefit.

Molecular description of ANGPT2 associated colorectal carcinoma

Angiopoietin-2 (ANGPT2) is a prognostic factor in metastatic colorectal cancer (CRC). Nevertheless, it remains to be elucidated which molecular characteristics make up the ANGPT2-related poor-prognosis CRC subset. Public transcriptomic datasets were collected from Gene Expression Omnibus GEO and with the TCGAbiolinks R-package for the TCGA. After appropriate normalization, differential expression analysis was performed using Benjamini and Hochberg method for false discovery rate. Plasma from two prospective clinical trials were used to investigate the clinical impact of ANGPT2-related biomarkers. In the 935 samples included in four annotated platforms (GPL) and derived from localized CRC, ANGPT2^hi expression conferred a worst overall survival (HR = 1.20; p = 0.02). CRC stage, ANGPT2^hi expression but not Consortium Molecular Subtype (CMS) predict overall survival in multivariate analysis. ANGPT2 expression was not correlated with a specific CMS nor to RAS, RAF, MSI, p53, CIN, CIMP genomic alterations. Gene expression analysis revealed that ANGPT2^hi CRC subset is characterized by angiogenesis-related gene expression, presence of myeloid cells, stromal organization and resistance to chemotherapy. A prognostic model was proposed using seric levels of ANGPT2, STC1 and CD138 in 97 mCRC patients. Our results provide evidence that ANGPT2 is a prognostic factor in localized CRC and defined a specific CRC subset with potential clinical implementation.

Liver-first approach to stage IV colon cancer with synchronous isolated liver metastases

Background

The only possibility for cure in patients with colon adenocarcinoma (CAC) with isolated liver metastases (ILM) is resection of both primary and metastatic tumors. Little is known about the implication of the sequence in which a colectomy and hepatectomy are performed on outcomes. This study analyzes whether resection sequence impacts clinical outcomes.

Methods

The National Cancer Database was queried for CAC cases with hepatic metastases from 2010-2015 with exclusion of extrahepatic metastases. We compared patients treated with a liver-first approach (LFA) to those treated with a colectomy-first or simultaneous approach using Kaplan Meier and multivariable Cox proportional hazards analysis.

Results

In 21,788 CAC patients identified, the LFA was uncommon (2%), but was associated with higher rates of completion resection of remaining tumor (41% vs. 22%, P<0.001). Patients selected for LFA were younger, less comorbid, and more commonly received upfront chemotherapy (P<0.05). The LFA was associated with increased median survival [34 months, 95% CI (30.5-39.6 months) vs. 24 months, 95% CI (23.7-24.6 months), logrank P<0.001] and decreased risk of death [HR 0.783; 95% CI (0.67-0.89), P=0.001].

Conclusions

The LFA to CAC with synchronous ILM is uncommon but is associated with greater likelihood of receiving chemotherapy prior to surgery and increased survival in selected candidates.

Peritoneal Metastases in Colorectal Cancer: Biology and Barriers

BACKGROUND

Advances in the molecular biology of tumor metastasis have paralleled the evolution in the management of metastatic disease from colorectal cancer. In this review, we summarize the current understanding of the mechanism of colorectal cancer metastases, in particular that of peritoneal metastases, as well as clinical data on the treatment of this disease.

METHODS

A review of relevant English literature using MEDLINE/PubMed on the biology of colorectal cancer metastases, determinants of oligometastasis, and use of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of metastatic colorectal cancer is presented.

RESULTS

Recognition of oligometastasis in the evolution of colorectal peritoneal metastases provides the theoretical framework for which cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy is considered. Clearly, a subset of patients benefit from peritoneal metastasectomy.

CONCLUSION

Advances in cancer biology and clinical imaging promise to expand the role of cytoreductive surgery with or without intraperitoneal chemotherapy in the management of peritoneal metastases from colorectal cancer.

Network Diffusion Promotes the Integrative Analysis of Multiple Omics

The development of integrative methods is one of the main challenges in bioinformatics. Network-based methods for the analysis of multiple gene-centered datasets take into account known and/or inferred relations between genes. In the last decades, the mathematical machinery of network diffusion—also referred to as network propagation—has been exploited in several network-based pipelines, thanks to its ability of amplifying association between genes that lie in network proximity. Indeed, network diffusion provides a quantitative estimation of network proximity between genes associated with one or more different data types, from simple binary vectors to real vectors. Therefore, this powerful data transformation method has also been increasingly used in integrative analyses of multiple collections of biological scores and/or one or more interaction networks. We present an overview of the state of the art of bioinformatics pipelines that use network diffusion processes for the integrative analysis of omics data. We discuss the fundamental ways in which network diffusion is exploited, open issues and potential developments in the field. Current trends suggest that network diffusion is a tool of broad utility in omics data analysis. It is reasonable to think that it will continue to be used and further refined as new data types arise (e.g. single cell datasets) and the identification of system-level patterns will be considered more and more important in omics data analysis.

Clinical Implication of Concordant or Discordant Genomic Profiling between Primary and Matched Metastatic Tissues in Patients with Colorectal Cancer

Purpose

The purpose of this study was to identify the concordant or discordant genomic profiling between primary and matched metastatic tumors in patients with colorectal cancer (CRC) and to explore the clinical implication.

Materials and Methods

Surgical samples of primary and matched metastatic tissues from 158 patients (335 samples) with CRC at Korea University Anam Hospital were evaluated using the Ion AmpliSeq Cancer Hotspot Panel. We compared genetic variants and classified them as concordant, primary-specific, and metastasis-specific variants. We used a combination of principal components analysis and clustering to find genomic groups. Kaplan-Meier curves were used to appraise survival between genomic groups. We used machine learning to confirm the correlation between genetic variants and metastatic sites.

Results

A total of 282 types of deleterious non-synonymous variants were selected for analysis. Of a total of 897 variants, an average of 40% was discordant. Three genomic groups were yielded based on the genomic discrepancy patterns. Overall survival differed significantly between the genomic groups. The poorest group had the highest proportion of concordant KRAS G12V and additional metastasis-specific SMAD4. Correlation analysis between genetic variants and metastatic sites suggested that concordant KRAS mutations would have more disseminated metastases.

Conclusion

Driver gene mutations were mostly concordant; however, discordant or metastasis-specific mutations were present. Clinically, the concordant driver genetic changes with additional metastasis-specific variants can predict poor prognosis for patients with CRC.

Oligometastatic Breast Cancer: Is This a Curable Entity? A Contemporary Review of the Literature

PURPOSE OF REVIEW

Oligometastatic breast cancer (OMBC) remains a poorly understood entity for which no standard of care exists at this time. This review will focus on our biologic understanding of OMBC and provide an update on current treatment strategies.

RECENT FINDINGS

The introduction of micro RNA expression profiling has advanced our understanding of the biologic underpinnings of OMBC. Although most of the data regarding treatment have come from retrospective studies, there are now prospective randomized trials reporting progression-free survival and overall survival improvements with stereotactic ablative radiotherapy (SABR). Ongoing studies designed to evaluate addition of SABR as well as other novel agents will further develop this field and provide new treatment options. A "cure" for OMBC remains elusive. With further basic research coupled with novel prospective trials, patients will hopefully enjoy increased progression-free survival and overall survival, and ideally a delay to more toxic systemic therapy.

Tumor biology and multidisciplinary strategies of oligometastasis in gastrointestinal cancers

More than 70% of gastrointestinal (GI) cancers are diagnosed with metastases, leading to poor prognosis. For some cancer patients with limited sites of metastatic tumors, the term oligometastatic disease (OMD) has been coined as opposed to systemic polymetastasis (PMD) disease. Stephan Paget first described an organ-specific pattern of metastasis in 1889, now known as the "seed and soil" theory where distinct cancer types are found to metastasize to different tumor-specific sites. Our understanding of the biology of tumor metastasis and specifically the molecular mechanisms driving their formation are still limited, in particular, as it relates to the genesis of oligometastasis. In the following review, we discuss recent advances in general understanding of this metastatic behavior including the role of specific signaling pathways, various molecular features and biomarkers, as well as the interaction of carcinoma cells with their tissue microenvironments (both primary and metastatic niches). The unique features that underlie OMD provide potential targets for localized therapy. As it relates to clinical practice, OMD is emerging as treatable with surgical resection and/or other local therapy options. Strategies currently being applied in the clinical management of OMD will be discussed including surgical, radiation-based therapy, ablation procedures, and the results of emerging clinical trials involving immunotherapy.

Immunotherapy with immune checkpoint inhibitors in colorectal cancer: what is the future beyond deficient mismatch-repair tumours?

Following initial success in melanoma and lung tumours, immune checkpoint inhibitors (ICIs) are now well recognized as a major immunotherapy treatment modality for multiple types of solid cancers. In colorectal cancer (CRC), the small subset that is mismatch-repair-deficient and microsatellite-instability-high (dMMR/MSI-H) derive benefit from immunotherapy; however, the vast majority of patients with proficient MMR (pMMR) or with microsatellite stable (MSS) CRC do not. Immunoscore and the consensus molecular subtype classifications are promising biomarkers in predicting therapeutic efficacy in selected CRC. In pMRR/MSS CRC, biomarkers are also needed to understand the molecular mechanisms governing immune reactivity and to predict their relationship to treatment. The continuous development of such biomarkers would offer new perspectives and more personalized treatments by targeting oncological options, including ICIs, which modify the tumour-immune microenvironment. In this review, we focus on CRC and discuss the current status of ICIs, the role of biomarkers to predict response to immunotherapy, and the approaches being explored to render pMMR/MSS CRC more immunogenic through the use of combined therapies.

Stereotactic Body Radiation Therapy of Adrenal Metastases: A Pooled Meta-Analysis and Systematic Review of 39 Studies with 1006 Patients

PURPOSE

To perform a systematic review and pooled meta-analysis of adrenal metastasis stereotactic body radiation therapy (SBRT) outcomes, treatment characteristics, and toxicity to define the efficacy and propose guidelines for intervention.

METHODS AND MATERIALS

We performed a comprehensive literature search of the Embase and PubMed databases of studies reporting outcome or toxicity data for photon-based SBRT of adrenal metastases in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We then conducted a meta-analysis to estimate pooled overall response, local control (LC), and overall survival and analyzed these outcomes in the context of dosimetric parameters and toxicity using metaregression.

RESULTS

Thirty-nine studies published between 2009 and 2019 reporting outcomes on 1006 patients were included. The median follow-up was 12 months, and the median biological equivalent dose (BED10, alpha/beta = 10) was 67 Gy. The pooled overall response was 54.6% (95% confidence interval [CI], 46.5%-62.5%). The pooled 1- and 2-year rates of LC were 82% (95% CI, 74%-88%) and 63% (95% CI, 50%-74%), respectively, and the pooled 1- and 2-year overall survival rates were 66% (95% CI, 57%-74%) and 42% (95% CI, 31%-53%), respectively. There was a strong positive association between SBRT dose and 1- and 2-year LC (P < .0001, P = .0002) and an association with 2-year OS (P = .03). Based on a metaregression of dose and LC, BED10 of 60 Gy, 80 Gy, and 100 Gy predicted 1-year LC of 70.5%, 84.8%, and 92.9% and 2-year LC of 47.8%, 70.1%, and 85.6%, respectively. The overall rate of grade 3 or higher toxicity was 1.8%.

CONCLUSIONS

SBRT of adrenal metastases provides good 1-year LC with an excellent safety profile, and dose escalation may be associated with improved LC. Prospective studies are needed to validate these findings and determine whether there are subsets of patients for whom adrenal metastasis-directed SBRT may confer a survival advantage.

Late Brain Oligometastases Diagnosed at Least 36 Months after Cancer Detection are Associated with Favorable Survival Outcome

Objective  The aim of this study was to investigate the impact of a long disease-free interval (at least 36 months from the first diagnosis of cancer) on survival in patients with brain oligometastases (maximum four lesions, no extracranial metastases). Methods This study involves a retrospective analysis in a group of 89 patients treated with different brain-directed approaches. Results We identified seven patients (8%) with an interval from cancer diagnosis to the development of brain metastases of at least 36 months. The median time interval was five months. The one-year survival rates were 80% (interval of at least 36 months) and 43% (shorter interval), respectively (p = 0.049). Correspondingly, a large difference in actuarial median survival was observed (39.9 months [95% confidence interval, 16.8-63.0 months] versus 9.7 months (95% confidence interval, 6.1-13.3 months). However, the two Kaplan-Meier curves were not statistically significantly different, p = 0.13. In addition to treatment-related differences, the two groups also differed with regard to the type of primary tumor (high versus low rates of non-small cell lung cancer) and gender. Conclusion Late dissemination was uncommon. The often applied strategy of effective local treatment for patients with brain-only oligometastases is warranted, especially if the disease-free interval had been at least 36 months. Larger studies are needed to fully understand the impact of confounding factors, such as gender and tumor biology.

Sanguinarine suppresses migration and metastasis in colorectal carcinoma associated with the inversion of EMT through the Wnt/β-catenin signaling

BACKGROUND

Unresectable lung or liver organ metastases of colorectal carcinoma (CRC) remain a major obstacle in clinical therapeutics. Epithelial to mesenchymal transition (EMT), a major cause of highly frequent metastasis in tumor, can be promoted by the Wnt/β-catenin pathway that is aberrantly activated in approximately 90% of CRC. This research aimed to elucidate the antimetastatic potential of sanguinarine (SG) in CRC and the underlying molecular mechanism.

METHODS

The in vitro anticancer effect of SG was determined via cell viability experiment and colony formation assay. Xenograft model of nude mice was used to confirm the antitumor effect of SG in vivo. The antimetastatic potential of SG was investigated by the metastasis model of nude mice, hematoxylin and eosin (H&E) staining, migration assay, and wound-healing analysis. Immunoblotting analysis, immunofluorescence staining, and immunohistochemistry assay were conducted to elucidate the molecular mechanism.

RESULTS

In this study, we reported that SG has a selective inhibitory effect on LoVo cells with metastatic characteristics. Furthermore, our results showed attenuation in the migration and metastatic ability of SG-treated LoVo cells and also decreased metastatic nodules of liver and lung in mice metastasis model. This was also confirmed at the molecular level via H&E staining. Further study revealed that SG had negative impacts on the Wnt/β-catenin pathway and EMT markers in LoVo cells both in vitro and in vivo.

CONCLUSIONS

Taken together, the antimetastatic potential of SG attributed to the suppression of the Wnt/β-catenin signaling, which further prevented EMT progression. SG may be of value in a potential therapy for the management of metastasis CRC.

Defining oligometastatic non-small cell lung cancer: A simulated multidisciplinary expert opinion

INTRODUCTION

Synchronous oligometastatic non-small cell lung cancer (NSCLC) definition varies from 1 metastasis in 1 organ (tumour-node-metastasis 8 [TNM8]), 1-3 metastases (European Society for Medical Oncology [ESMO]), ≤3 metastases (including mediastinal nodes [MLN]) after systemic treatment to 3-5 metastases in ongoing trials. A single definition is however needed to design/compare trials. To assess oligometastatic NSCLC definitions used by clinical experts in daily practice and its evolution, we redistributed a 2012 case-based survey (Dooms, the World Congress of Lung Cancer 2013).

METHODS

In December 2017, 10 real-life multidisciplinary team (MDT) discussed patients (good condition, no significant comorbidities, 18F-fluorodeoxyglucose positron emission tomography/brain magnetic resonance imaging staged, all < 5 metastases, 9/10 ≤ 3 metastases, oncogene-addicted or wild-type) were distributed to 33 international NSCLC experts involved in the European Organisation for Research and Treatment of Cancer oligometastatic NSCLC consensus group, questioning is this oligometastatic disease and if oligometastatic, which treatment proposal. The answers provided in 2017 were compared with the 2012 answers; real-life treatment and survival of the patients was added.

RESULTS

Twenty-six of 33 experts (24 centres) replied: 8 medical oncologists, 7 pulmonologists, 7 radiation oncologists, 4 thoracic surgeons. Sixty-two percent of respondents discussed the cases with their MDT. One case had 100% oligometastatic consensus, and 3 cases had >90% consensus; the number of treatment proposals varied between 3 and 8. Radical treatment was more often offered in case of single metastasis or N0. Compared with 2012, there was a trend towards a more conservative oligometastatic definition and chemotherapy was more frequently included in the treatment proposal.

CONCLUSIONS

Oligometastatic NSCLC definition was conservative. The number of organs, MLN status and radical treatment possibility seem to be components of daily practice oligometastatic definition.

Radioablation +/- hormonotherapy for prostate cancer oligorecurrences (Radiosa trial): potential of imaging and biology (AIRC IG-22159)

BACKGROUND

Prostate cancer (PCa) is the second most common cancer among men. New imaging-modalities have increased the diagnosed patients with limited number of metastasis after primary curative therapy, introducing so-called oligometastatic state. Stereotactic body radiotherapy (SBRT) is emerging as a low-toxicity treatment to erase PCa localizations and postpone androgen deprivation therapy (ADT). A deeper understanding of the predictive role of biomarkers is desirable for a targeted treatment selection and surveillance programs. The aims of the RADIOSA trial are: 1. Compare SBRT +/- ADT for oligorecurrent-castration-sensitive PCa (OCS-PCa) in terms of efficacy, toxicity and Quality of Life (QoL). 2. Develop biology/imaging based prognostic tool that allows identifying OCS-PCa subclasses.

METHODS

This is a randomized phase II clinical trial, recruiting 160 OCS-PCa in 3 years, with progression-free survival (PFS) as primary endpoint. Three tasks will be developed: 1. Randomized clinical study (3 years for accrual and 2 years for follow-up and data analysis); 2. Imaging study, including imaging registration and METastasis Reporting and Data System (MET-RADS) criteria; 3. Pre-clinical study, development of a biobank of blood samples for the analysis of neutrophil-to-lymphocyte ratio and preparatory for a subsequent miRNA profiling. We aim to determine which arm is justified for testing in a subsequent Phase III trial. A decision-tree algorithm, based on prognosis, biological phenotype and imaging profile, will be developed.

DISCUSSION

Recruiting will start in July 2019. SBRT will allow obtaining excellent PFS, local control, QoL and low toxicity. In SBRT arm, ADT deferral will allow for a drug-holiday, delaying the detrimental impact on QoL. A sufficient number of blood samples will be collected to perform biological patient profiling. A stratification tool will be established with an analysis of morphological and functional imaging, based on the use of MET-RADS criteria. So, in conclusion, RADIOSA aims to define the optimal management of bone/nodal PCa relapses in a SBRT regimen. This study will increase our knowledge on low-burden metastatic PCa in the era of high precision and high technology personalized medicine, offering highly effective therapy in terms of clinical outcome and cost-effectiveness.

TRIAL REGISTRATION

The RADIOSA study was prospectively registered at clinicaltrials.gov ( NCT03940235 , May 2019).

The Tumor Microenvironment in Colorectal Cancer Therapy

The current standard-of-care for metastatic colorectal cancer (mCRC) includes chemotherapy and anti-angiogenic or anti-epidermal growth factor receptor (EGFR) monoclonal antibodies, even though the addition of anti-angiogenic agents to backbone chemotherapy provides little benefit for overall survival. Since the approval of anti-angiogenic monoclonal antibodies bevacizumab and aflibercept, for the management of mCRC over a decade ago, extensive efforts have been devoted to discovering predictive factors of the anti-angiogenic response, unsuccessfully. Recent evidence has suggested a potential correlation between angiogenesis and immune phenotypes associated with colorectal cancer. Here, we review evidence of interactions between tumor angiogenesis, the immune microenvironment, and metabolic reprogramming. More specifically, we will highlight such interactions as inferred from our novel immune-metabolic (IM) signature, which groups mCRC into three distinct clusters, namely inflamed-stromal-dependent (IM Cluster 1), inflamed-non stromal-dependent (IM Cluster 2), and non-inflamed or cold (IM Cluster 3), and discuss the merits of the IM classification as a guide to new immune-metabolic combinatorial therapeutic strategies in mCRC.